Animating with Footsteps

Animating with Footsteps

Modifying Footsteps

 

Autodesk 3ds Max Tutorials > Character Animation Tutorials > Animating with Footsteps > 

Creating a Distinctive Walk

In this lesson, using automatically created motion as the basis, you’ll animate a biped walking with a rolling, springy step.

The automatic footsteps generate a starting point for you. You’ll then change the automatic walk into something more expressive and distinctive. This sophisticated yet simple approach results in a natural-looking motion that you can create quickly.

Set up the lesson:

1. Reset 3ds Max.
2. From the tutorials\character_animation\footstep_animation folder, open walk_start.max.

   In this file, a biped is standing near the origin.

   

   Biped near origin of grid

3. Maximize the Perspective viewport by pressing Alt+W.
4. Click any part of the biped to select it.

   A white box outlines the selected body part.

5. Open the Motion panel.

   The Biped controls are displayed.

   Next you’ll turn on Footstep Mode. If Figure Mode was on, it turns off automatically.

Create multiple footsteps:

1. On the Motion panel, in the Biped rollout, turn on Footstep Mode.

   The Footstep mode button turns yellow, and the Footstep Creation and Footstep Operations rollouts are displayed.

2. In the Footstep Creation rollout, click Create Multiple Footsteps.

   The Create Multiple Footsteps: Walk dialog is displayed. Here you see many parameters for creating multiple footsteps. You’ll only change the number of footsteps, leaving the other defaults as they are.

3. In the General group of the Create Multiple Footsteps: Walk dialog, change Number Of Footsteps to 8, and then click OK.

   Footprints are displayed in white in the viewport. These are inactive footsteps. They do not yet control any animation for the biped. If you click the Play Animation button, the biped won't move.

   

   Inactive footsteps

4. In the Footstep Operations rollout, click Create Keys For Inactive Footsteps.

   The footsteps are activated. Animation keys are created for the biped.

5. Play the animation.

   The biped walks.

   

   The biped takes a step.

   

   The biped takes another step.

   

   The biped keeps on walking.

6. On the Biped rollout, turn off the Footstep Mode button.

   Notice that the first footstep is numbered 0, and the last footstep is numbered 7.

7. In the Track Selection Rollout, click the Body Horizontal button. This selects the horizontal position track for the center of mass (COM) object.

   The track bar displays keys for the length of the animation.

   

   Body Horizontal keys

8. In the Track Selection rollout, click the Body Vertical button. This turns off Body Horizontal.

   Keys are visible at the same frames on the track bar.

   

   Body Vertical keys

9. Play the animation.

   The biped walks, but without much character.

   In the following procedures, you'll begin individualizing the motion by adjusting the keys for the Body Horizontal, Vertical, and Rotation tracks. You'll exaggerate the rotation of the center of mass to create a more energetic walk.

Adjust body rotation keys:

1. In the Perspective viewport, use Arc Rotate to shift the view so that the biped is walking toward you. Then move the time slider to frame 0.

   

   Be sure a part of the biped is still selected. In the Track Selection rollout, click the Body Rotation button.

   The Transform gizmo displays for rotation. The track bar displays the rotation keys.

   

2. On the 3ds Max status bar, click the Key Mode button to turn on Key mode.

   Key mode lets you use Previous and Next Key buttons to jump between keyframes for the selected object. You can also use the < and > keys on the keyboard to move between keyframes without clicking the mouse.

3. Press > on the keyboard to move the time slider to frame 24.
4. Use the Transform gizmo to adjust the body rotation. Move your cursor over the gizmo; when the circle turns yellow and the X in the center turns red, click and drag to rotate. If you can't see the X, zoom into the viewport. Rotate 5 to 10 degrees about the X axis to move the hips down toward the leg that is in motion. When you rotate, one foot will cross the other.
   TipThe rotation is displayed in yellow text above the Transform gizmo, and also in the Coordinate fields on the status bar. You can use the plus (+) and minus (–) keys to change the size of the Transform gizmo.

   

   Rotation of the center of mass object about the X axis

5. On the Motion panel, open the Key Info rollout and click the Set Key button.

   When you set the key, the biped will shift position slightly. In the viewport, you can see that the blue foot is no longer crossing the green.

   

   Biped foot snaps away from the other foot.

   What is happening is that the foot, calf, and thigh bones are being controlled by the footstep gizmos. The footsteps represent a pair of keys with IK Blend set to 1 and the Join To Prev IK key turned on. When you set the key, these settings force the foot, calf, and leg bones back into the correct path for walking.

6. Click Next Key three times to move to frame 40.
7. Rotate the Transform gizmo –6 to –10 degrees about the X axis.

   

   Negative rotation with blue foot in contact with the ground

8. Slowly go through the rest of the rotation keys, repeating this process. At keys where the blue foot comes in contact with the ground (frames 40, 69, and 99), rotate about the X axis in a negative direction, then set a key. At keys where the green foot is down (frames 55, 84, 116), rotate about the X axis in a positive direction, then set a key.

   

   Positive rotation at frame 54

9. Repeat this pattern until you have finished rotating the COM at the end of the animation. Don't make your adjustments too precise. Slight variations from frame to frame make the motion look more natural.

   When you are done, play the animation and notice the increased hip swings that result from rotating the center of mass back and forth.

10. On the Biped rollout, click Save File and save the file as mywalk.bip.

    If you load the newly saved mywalk.bip file into a scene containing a skinned character, the character will swing its hips according to the instructions you saved in this file. Play the animation to determine if you need to adjust it. For instance, Dr. X (from the quick start tutorial) has huge feet, which may need to be moved further apart so they don't pass through the legs accidentally.

    

    Dr. X character with distinctive walk

Add spring to the step:

1. Continue from before, or load the mywalk.bip file that you saved earlier.

   To load a BIP file, create or select a biped. On the Motion panel > Biped rollout, click Load File and open the file. This transfers all the movement information in the file to the biped.

2. On the Track Selection rollout, click the Body Vertical button.

   This selects the vertical position track for the center of mass object.

3. Turn on Key Mode, if it isn't already on.
4. Starting at frame 0, move through the animation using the < and > keys. When you come to a frame where either a green or blue foot comes in contact with the ground, move the COM down just a few units.

   The knees bend because the feet are controlled by the footsteps.

5. After making a change at a frame, click the Set Key button on the Key Info rollout.

   This sets a key for the change you've made in the viewport; otherwise, the change is discarded.

6. Play the animation.

   The biped walks with newfound bounce.

7. On the Biped rollout, click Save File. Name the file mywalk2.bip.

Add arm and hand motions:

Arm and hand motions are an integral part of an individual’s gait. In the following sequence, you'll customize the arm motion by moving the hands and rotating the arms.

You previously created keyframes using the Set Key button; however, for this technique, you'll use Auto Key instead.

1. Continue from before, or load mywalk2.bip, the file you saved in the previous section. If you prefer, you can begin at the end of the last procedure by opening springystep.max.
2. Turn on the Auto Key button.
3. Move the time slider to frame 0.
4. Dragging the time slider to the right, flip through the frames of animation. Drag forward and backward, and watch the how the arms and legs swing. Study the motion carefully.

   When the green foot is extended, the blue arm swings forward. When the blue foot swings out, the green arm swings forward. See if you can find the frame at which the hand extends the farthest forward.

5. In the viewport, select the green hand of the biped (Bip01 RHand).

   The track bar displays the keys for the hand.

6. Move the time slider to frame 30.

   There is a key in track bar at that frame for the hand object.

7. Right-click the hand, and choose Move from the quad menu.

   Using the Transform gizmo, move the hand approximately 10 units upward on the Z axis.

   By moving the hand, you've also rotated the two arm bones. The keys for the hand and arm bones are stored on a single track.

   

   The hand moved upward

8. Select the Bip01 R UpperArm object, then right-click and choose Rotate. Rotate the upper arm approximately –30 degrees about the Z axis.

   

   The upper arm rotated around the Z axis

9. Rotate the upper arm approximately 20 degrees about the Y axis, so the elbows are flying out and away from the body.
10. Select the forearm object (Bip01 R Forearm) and rotate it so the hand moves closer to the chest.

    

    The hand rotated close to the chest

    You can position the arm using forward kinematics (the rotation of the parent objects) or inverse kinematics, using position transform on the end of the chain: in this case, the position of the wrist. You can also rotate the hands.

11. Use Arc Rotate to adjust the view angle so you can see the angle of the other arm behind the biped.

    

    View of the arm behind the biped

12. Select the blue hand, and right-click to choose Move. Move the hand further away from the biped's body. Then move the blue hand upward on the Z axis so the elbow bends slightly.

    

13. Move the time slider back and forth to observe the animation so far.
14. Repeat the process at frames 60 and 90.
15. Repeat for the other side at frames 45 and 75.
    TipIf you want exact duplication of these arm positions, you can use the tools in the Copy/Paste rollout. Select both arm assemblies, create a collection, then use Copy Posture and Paste Opposite at the correct frames. See Creating a Simple Freeform Animation for information on using those features.
16. Play the animation.

    Save it as mywalk3.bip.

17. To see your work on a skinned character, open cs4_qs_DrX04.max from the \tutorials\character_animation\quick_start folder, and then load your mywalk3.bip file. For comparison, you can also load distinctive_walk_final.bip from the \tutorials\character_animation\footstep_animation folder. Remember to select part of the biped to access the Biped rollout.

    

    Dr. X with spring in his step

Add head motions:

You can edit the head motion to make the biped’s walk look more natural. In this procedure, you'll add head rotations to accentuate the COM rotation.

1. Turn on Auto Key, if it isn’t on already.
2. Turn on Key mode, if it isn’t on already.
3. Move the time slider to frame 0.
4. In the Perspective viewport, select the biped's head using Rotate on the 3ds Max main toolbar.
5. Rotate the head down as if the biped is asleep.

   

   The head rotated downward

6. Move the time slider to the next keyframe by pressing the > key.
7. Keyframe rotations for the head. You can rotate the head to counterbalance the angle of the shoulders. Or, you can rotate the head in the opposite direction so it follows the rotation of the COM. Each rotation will give a different result. Extreme rotations should be avoided. Also, be careful to put the rotations only on existing keys.

   

   Rotate the head to follow the movement, or rotate the head to oppose the shoulders.

8. Continue to jump through the head's keys, setting rotations of your choice to animate the head.

   Natural head motion is smooth, so the orientations should change gradually from one key to the next.

9. Turn off Auto Key and Key Mode.
10. Play the animation, and notice how much the biped’s head movements add to the animation.

    You can now save your work as mywalk4.bip. You can check your file against head_rotate_with.bip and head_rotate_against.bip.

    

    Dr. X's distinctive walk with head rotation